Concrete roadways are made with concrete sections separated from each other by expansion slots to enable thermal expansion and contraction of the roadway. In ordinary surface roads slots can simply be filled with resilient bituminous material or the like. However, for bridges and other elevated roadways and multilevel concrete parking decks other more elaborate means is required to effectively and durably fill and seal the slots, at the same time enabling expansion and contraction of the adjacent concrete sections due to changes in temperature.
Numerous preformed rubber or other elastomeric sealing members, molded to various configurations, have been proposed for use in the expansion slots, such premolded member being mechanically secured within the slots as by bolts or the like. It is also known to recess the edges of the concrete sections adjacent the expansion slot and then secure the elastomeric member into the slot by placing it with its edges in the recesses and then securing it in place by filling the recesses with a resin-modified concrete or the like. The chief difficulty with all such structures is that they lack durability and after a relatively short period cease to provide an effective seal and with this, in turn, leading to deterioration of the entire joint structure.
It is also known to use a metal plate to bridge the expansion slot, the plate being secured to the recess in one of the concrete sections and being movable relative to recesses in the other of the concrete sections, and with the recess portions above the metal plate then being filled with an elastomeric material which is molded in situ, and with a thin layer of material being used between the metal plate and the molded in situ elastomer to inhibit bonding of the elastomer to the metal plate thereby enabling relative movement therebetween. However, such structure is very demanding of close quality control in construction and requires compromise in the choice of the elastomer material. Further, even with optimum choice of material and optimum quality control in construction, such structure nevertheless is lacking in long term durability to assure continued effective sealing of the expansion slot.